JP3147316B2 - Method for manufacturing semiconductor light emitting device - Google Patents
Method for manufacturing semiconductor light emitting deviceInfo
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- JP3147316B2 JP3147316B2 JP21917991A JP21917991A JP3147316B2 JP 3147316 B2 JP3147316 B2 JP 3147316B2 JP 21917991 A JP21917991 A JP 21917991A JP 21917991 A JP21917991 A JP 21917991A JP 3147316 B2 JP3147316 B2 JP 3147316B2
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- layer
- aln
- light emitting
- sapphire
- emitting device
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、可視（赤外）から紫外
で発光する半導体発光素子の作製方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor light emitting device which emits light from visible (infrared) to ultraviolet.
【０００２】[0002]
【従来の技術】ＩＩＩ族窒化物半導体ＩｎＮ，ＧａＮ，
ＡｌＮ，ＩｎＧａＡｌＮでは大型のバルク単結晶が成長
できないため、従来サファイアを基板として用いたエピ
タキシャル成長が一般に行われてきた。しかし、サファ
イアと上記ＩＩＩ族窒化物半導体の間には１１〜２３％
の格子不整合および〜２×１０−６〔ｄｏｇ−１〕の熱
膨張係数差が存在し、このために生じる不整合転位 及
び熱歪みがＩＩＩ族窒化物半導体エピタキシャル膜の結
晶性・電気的光学的特性の向上の妨げとなっている。ま
た、両者の化学的性質の違いにより生じる界面エネルギ
のため、サファイア上に直接成長したＩＩＩ族窒化物半
導体エピタキシャル膜は顕著な三次元成長を起こし、表
面形態の平坦化・結晶性の向上が難しい。この結果、サ
ファイア基板上に作製したＩｎ１−ｘ−ｙＧａｘＡｌｙ
Ｎ（０≦ｘ≦１，０≦ｘ＋ｙ≦１）発光素子は発光効率
や素子寿命を十分に向上できないという問題があった。2. Description of the Related Art Group III nitride semiconductors InN, GaN,
Since large bulk single crystals cannot be grown on AlN or InGaAlN, epitaxial growth using sapphire as a substrate has conventionally been generally performed. However, between sapphire and the group III nitride semiconductor, 11 to 23%
Lattice mismatch and a thermal expansion coefficient difference of ２2 × 10 −6 [dog −1 ], and the mismatch dislocations and thermal strain that occur due to this cause crystallinity and electrical optics of the group III nitride semiconductor epitaxial film. This hinders the improvement of the mechanical characteristics. In addition, due to the interfacial energy caused by the difference in chemical properties between the two, the group III nitride semiconductor epitaxial film directly grown on sapphire undergoes remarkable three-dimensional growth, making it difficult to flatten the surface morphology and improve the crystallinity. . As a result, In 1-xy Ga x Al y fabricated on the sapphire substrate
The N (0 ≦ x ≦ 1, 0 ≦ x + y ≦ 1) light emitting element has a problem that the luminous efficiency and the element life cannot be sufficiently improved.
【０００３】格子不整合の大きなヘテロエピタキシャル
成長では、基板・エピタキシャル膜の中間的な物理定数
をもつ材料を介して成長を行うことによりエピタキシャ
ル膜の品質を向上することができる。サファイア上のＩ
ＩＩ族窒化物半導体成長ではＡｌＮ層を介した成長が有
効である。これはＡｌＮがサファイアとＩＩＩ族窒化物
半導体の中間的な格子定数と熱膨張係数をもつため、格
子不整合と熱歪みが効率的に緩和される結果である。ま
た、ＡｌＮとＩＩＩ族窒化物半導体は化学的性質が近
く、両者の間の界面エネルギも小さい。このため、平坦
なＡｌＮ層を形成できさえすればその上に成長するエピ
タキシャル膜の三次元成長を抑制できる。In heteroepitaxial growth with a large lattice mismatch, the quality of the epitaxial film can be improved by growing the material through a material having an intermediate physical constant between the substrate and the epitaxial film. I on sapphire
In growing a group II nitride semiconductor, growth through an AlN layer is effective. This is a result of the fact that AlN has an intermediate lattice constant and thermal expansion coefficient between sapphire and a group III nitride semiconductor, so that lattice mismatch and thermal distortion are efficiently reduced. Further, AlN and the group III nitride semiconductor have similar chemical properties, and the interface energy between them is small. Therefore, as long as a flat AlN layer can be formed, three-dimensional growth of an epitaxial film grown thereon can be suppressed.
【０００４】従来、以上の目的のＡｌＮ形成方法として
は、 サファイア基板をＮＨ３，Ｎ２Ｈ２、あるいは
有機アミン等の窒素原料ガス雰囲気中で熱処理すること
により基板表面を単結晶ＡｌＮ化する方法、 ＡｌＮ
の単結晶成長が可能な高温に保ったサファイア基板上に
有機アルミニウム，ハロゲン化アルミニウムあるいは金
属アルミニウム蒸気等のアルミニウム原料ガスと窒素原
料ガスを供給し単結晶ＡｌＮ層を堆積する方法、 ５
００〜１０００℃の低温でアルミニウム原料ガスと窒素
原料ガスを供給し、数１００〜１０００Åの多結晶もし
くはアモルファスＡｌＮ層を堆積した後、これより高温
でアニールすることにより単結晶化する方法があった。Conventionally, as the above-mentioned AlN forming method, there is a method in which a sapphire substrate is heat-treated in an atmosphere of a nitrogen source gas such as NH 3 , N 2 H 2 or organic amine to convert the substrate surface into single-crystal AlN. , AlN
A method of supplying an aluminum source gas such as organic aluminum, aluminum halide or metal aluminum vapor and a nitrogen source gas onto a sapphire substrate kept at a high temperature capable of growing a single crystal of, and depositing a single crystal AlN layer;
There is a method of supplying an aluminum source gas and a nitrogen source gas at a low temperature of 00 to 1000 ° C., depositing a polycrystalline or amorphous AlN layer of several 100 to 1000 °, and then annealing at a higher temperature to form a single crystal. .
【０００５】の方法では、数１０Åの窒化層を再現性
良く形成できる上、この単結晶ＡｌＮ層は傾斜的な組成
変化を伴うためわずか数１０Åの領域で効果的に格子不
整合を緩和する。しかしながら詳細な観察の結果、この
方法で作製したＡｌＮ層は１０Åのオーダーで表面荒れ
を起こしていることが明らかになった。このことに起因
して、の方法で作製したＡｌＮ層上にエピタキシャル
成長を行うと、膜厚の増加に伴いこの凹凸が強調され平
坦な表面形状が得られない。According to the method described above, a nitride layer of several tens of degrees can be formed with good reproducibility, and since this single-crystal AlN layer involves a gradient composition change, lattice mismatch can be effectively reduced in a region of only several tens of degrees. However, a detailed observation revealed that the AlN layer produced by this method had a surface roughness of the order of 10 °. Due to this, when epitaxial growth is performed on the AlN layer manufactured by the method described above, the unevenness is emphasized as the film thickness increases, and a flat surface shape cannot be obtained.
【０００６】また、の方法で作製したＡｌＮ層は高温
で膜成長を行うため、三次元成長核の形成が避けられな
い。以上のことより、及びの方法で作製したＡｌＮ
バッファ層は、その上に成長したエピタキシャル膜の電
気的光学的特性の向上には効果を有するものの、三次元
成長の抑制には無力である。Further, since the AlN layer produced by the method described above grows at a high temperature, formation of a three-dimensional growth nucleus is inevitable. From the above, the AlN produced by the above method and
The buffer layer is effective in improving the electrical and optical characteristics of the epitaxial film grown thereon, but is ineffective in suppressing three-dimensional growth.
【０００７】の方法は、三次元成長が起こらないよう
な低温でＡｌＮ膜を堆積するため平坦なバッファ層の形
成が可能となる。この結果、その上に成長するエピタキ
シャル膜の三次元成長が抑制され、表面形態の平坦化・
結晶性の向上を達成できる。ところで、サファイア上に
低温堆積したＡｌＮ層にはアニールによって単結晶化す
るための最大膜厚ｄｍａｘと、連続膜となるために必要
な最低膜厚ｄｍｉｎが存在し、膜厚をｄｍａｘとｄ
ｍｉｎ間に制御する必要がある。通常、ｄｍａｘは１０
００Å程度、ｄｍｉｎは１００〜２００Åである。さら
に、ＡｌＮバッファ層厚がこの範囲であっても、エピタ
キシャル膜の特性はＡｌＮバッファ層厚に強く依存す
る。しかしながら、サファイア基板上に直接ＡｌＮ層を
堆積する従来の方法では、膜厚の制御性が悪いという問
題があった。この原因を把握するため、成長初期段階に
おけるサファイア上ＡｌＮの成長膜厚の成長時間依存性
を詳細に調べた結果、図５に示すような再現性のない１
〜３分の時間遅れが存在することが明らかになった。こ
の時間遅れはサファイアとＡｌＮの化学的性質の差に起
因し、基板上におけるアルミニウム原料ガスの濃度があ
る濃度に達するまで堆積が開始しないことが原因であ
る。これはサファイア上に直接ＡｌＮを堆積しようとす
る限り本質的な問題である。According to the method described above, since an AlN film is deposited at such a low temperature that three-dimensional growth does not occur, a flat buffer layer can be formed. As a result, the three-dimensional growth of the epitaxial film grown thereon is suppressed, and the surface morphology is flattened.
Improved crystallinity can be achieved. By the way, the AlN layer deposited at low temperature on sapphire has a maximum film thickness d max for single crystallization by annealing, and a minimum film thickness d min necessary for forming a continuous film, and the film thickness is d max . d
It is necessary to control during the min . Usually, d max is 10
About 00 °, d min is 100 to 200 °. Furthermore, even when the AlN buffer layer thickness is within this range, the characteristics of the epitaxial film strongly depend on the AlN buffer layer thickness. However, the conventional method of directly depositing an AlN layer on a sapphire substrate has a problem that the controllability of the film thickness is poor. In order to understand the cause, the growth time dependence of the growth film thickness of AlN on sapphire in the initial stage of growth was examined in detail. As a result, as shown in FIG.
It was found that there was a time delay of ~ 3 minutes. This time delay is caused by a difference in chemical properties between sapphire and AlN, and is caused by the fact that deposition does not start until the concentration of the aluminum source gas on the substrate reaches a certain concentration. This is an essential problem as long as one intends to deposit AlN directly on sapphire.
【０００８】[0008]
【発明が解決しようとする課題】本発明は上記の問題点
を解決するためなされたもので、その目的は、ＩＩＩ族
窒化物半導体Ｉｎ１−ｘ−ｙＧａｘＡｌｙＮ（０≦ｘ≦
１，０≦ｘ＋ｙ≦１）エピタキシャル膜の高品質化によ
る高効率・長寿命の半導体発光素子を作製する方法を提
供することにある。SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a group III nitride semiconductor In 1-xy Ga x Al y N (0 ≦ x ≦
1,0 ≦ x + y ≦ 1) It is an object of the present invention to provide a method for manufacturing a highly efficient and long-life semiconductor light emitting device by improving the quality of an epitaxial film.
【０００９】[0009]
【課題を解決するための手段】上記の目的を達成するた
め、本発明は、サファイア基板を窒素原料ガス雰囲気中
で熱処理し、基板表面を単結晶ＡｌＮ化する第１の工程
と、窒化層上にアルミニウム原料ガスとの反応により多
結晶もしくはアモルファスＡｌＮバッファ層を堆積する
第２の工程と、前記ＡｌＮバッファ層をその堆積温度よ
りも高温でアニールする第３の工程と、ＩｎＧａＡｌＮ
層を少なくとも１層含む発光層を形成する第４の工程と
を含むことを特徴とする半導体発光素子の作製方法を発
明の要旨とするものである。換言すれば、本発明によっ
て作製された半導体発光素子は、サファイア基板表面に
形成した窒化層と該窒化層上に堆積した多結晶もしくは
アモルファスＡｌＮバッファ層を含むことを最も主要な
特徴とする。In order to achieve the above object, the present invention provides a first step of heat-treating a sapphire substrate in a nitrogen source gas atmosphere to convert the substrate surface into single-crystal AlN, A second step of depositing a polycrystalline or amorphous AlN buffer layer by a reaction with an aluminum source gas, a third step of annealing the AlN buffer layer at a temperature higher than the deposition temperature,
And a fourth step of forming a light-emitting layer having at least one layer. In other words, the semiconductor light emitting device manufactured according to the present invention is most characterized by including a nitride layer formed on the surface of the sapphire substrate and a polycrystalline or amorphous AlN buffer layer deposited on the nitride layer.
【００１０】従来のＡｌＮ層を介してサファイア上に作
製した半導体発光素子とはその構造及び作製方法におい
て以下の点が異なる。すなわち、窒化処理により表面を
単結晶ＡｌＮ化したサファイア基板上に作製した半導体
発光素子とは、表面窒化層に接して低温堆積後アニール
により単結晶化したＡｌＮバッファ層を含む点が異な
る。サファイア基板上にＡｌＮの単結晶成長温度以上の
高温で堆積したＡｌＮバッファ層を介して作製した半導
体発光素子とは、ＡｌＮバッファ層をサファイア表面窒
化層を介して堆積している点及びＡｌＮ層の堆積を平坦
なＡｌＮ層が得られる低温で行い、その後、これより高
温でアニールすることにより単結晶化する点が異なる。
また、低温堆積した後これより高温でアニールすること
により単結晶化したＡｌＮバッファ層を介して作製した
半導体発光素子とは、ＡｌＮバッファ層をサファイア表
面窒化層を介して堆積している点が異なる。A semiconductor light emitting device manufactured on sapphire via a conventional AlN layer differs in the structure and manufacturing method from the following points. That is, a semiconductor light emitting device manufactured on a sapphire substrate whose surface is made into single crystal AlN by nitriding treatment is different in that it includes an AlN buffer layer which is in contact with a surface nitride layer and which is single crystallized by annealing after low-temperature deposition. A semiconductor light emitting device manufactured through an AlN buffer layer deposited on a sapphire substrate at a high temperature equal to or higher than the AlN single crystal growth temperature means that an AlN buffer layer is deposited via a sapphire surface nitride layer and The difference is that the deposition is performed at a low temperature at which a flat AlN layer can be obtained, and thereafter, annealing is performed at a higher temperature to achieve single crystallization.
Further, the semiconductor light emitting device is different from the semiconductor light emitting device manufactured through the single crystallized AlN buffer layer by annealing at a higher temperature after being deposited at a low temperature, in that the AlN buffer layer is deposited via the sapphire surface nitride layer. .
【００１１】[0011]
【作用】本発明の作製方法によれば、サファイア基板表
面の窒化層上に多結晶もしくはアモルファスＡｌＮバッ
ファ層を堆積し、その後ＡｌＮバッファ層を高温でアニ
ールして単結晶化している。本発明では、前記構成によ
りバッファ層の膜厚制御性が格段に向上し、さらにその
上に形成するＩｎ１−ｘ−ｙＧａｘＡｌｙＮ層の平坦性
が向上するという顕著な作用・効果を有する。According to the manufacturing method of the present invention, a polycrystalline or amorphous AlN buffer layer is deposited on a nitride layer on the surface of a sapphire substrate, and then the AlN buffer layer is annealed at a high temperature to be single crystal. According to the present invention, a remarkable function and effect that the thickness controllability of the buffer layer is remarkably improved by the above configuration, and the flatness of the In 1-xy Ga x Al y N layer formed thereon is further improved. Having.
【００１２】[0012]
【実施例】次に本発明の実施例について説明する。な
お、実施例は一つの例示であって、本発明の精神を逸脱
しない範囲で、種々の変更あるいは改良を行い得ること
は言うまでもない。Next, an embodiment of the present invention will be described. The embodiment is merely an example, and it goes without saying that various changes or improvements can be made without departing from the spirit of the present invention.
【００１３】図１は本発明によって作製された半導体発
光素子の一例を説明する図であって、発光素子の断面を
示す。本発光素子はサファイア（０００１）基板１の表
面に形成した窒化層２（窒化深さ５０Å）、膜厚５００
ÅのＡｌＮバッファ層３、膜厚５μｍのＳｉドープｎ型
低抵抗ＧａＮ層４、膜厚０．５μｍのＺｎドーピングに
より半絶縁化したＧａＮ発光層５、半絶縁層の電極６、
ｎ型低抵抗層のオーミック電極７からなる。電極６に正
の電圧を電極７に負の電圧を加えると発光層５は４８０
ｎｍの波長で発光した。最大光出力は０．８ｍＷであ
り、外部量子効率は０．２％であった。この例では、ｎ
型低抵抗層、半絶縁層としてＧａＮを用いたが、これに
代えてＩｎ１−ｘ−ｙＧａｘＡｌｙＮ（０≦ｘ≦１，０
≦ｘ＋ｙ≦１）を用いることにより発光波長を３００〜
８００ｎｍの範囲で変化させることができる。FIG. 1 is a view for explaining an example of a semiconductor light emitting device manufactured according to the present invention, and shows a cross section of the light emitting device. This light emitting device has a nitride layer 2 (nitride depth of 50 °) formed on the surface of a sapphire (0001) substrate 1 and a film thickness of 500.
Å, an AlN buffer layer 3, a 5 μm-thick Si-doped n-type low-resistance GaN layer 4, a 0.5 μm-thick GaN light emitting layer 5 semi-insulated by Zn doping, a semi-insulating layer electrode 6,
It comprises an ohmic electrode 7 of an n-type low resistance layer. When a positive voltage is applied to the electrode 6 and a negative voltage is applied to the electrode 7, the light emitting layer 5
Emitted at a wavelength of nm. The maximum light output was 0.8 mW and the external quantum efficiency was 0.2%. In this example, n
-Type low-resistance layer, GaN is used as the semi-insulating layer, in place of this In 1-x-y Ga x Al y N (0 ≦ x ≦ 1,0
≦ x + y ≦ 1), the emission wavelength becomes 300 to
It can be changed in the range of 800 nm.
【００１４】図２は本発明によって作製された半導体発
光素子の他の例の断面を示す。本発光素子はサファイア
（０００１）基板１０の表面に形成した窒化層１１（窒
化深さ５０Å）、膜厚５００ÅのＡｌＮバッファ層１
２、膜厚５μｍのＳｉドープｎ型ＩｎＡｌＮクラッド層
１３、膜厚０．５μｍのアンドープＩｎＧａＮ活性層１
４、膜厚２μｍのＭｇドープｐ型ＩｎＡｌＮクラッド層
１５、ｐ型クラッド層のオーミック電極１６、ｎ型クラ
ッド層のオーミック電極１７からなる。ここに示したＩ
ｎＡｌＮ層１３及びＩｎＧａＮ層１４は、互いに格子整
合し、クラッド層のバンドギャップエネルギが活性層の
バンドギャップエネルギに比べ０．３ｅＶ以上大きくな
るように組成を選んだ。この結果、クラッド層の屈折率
は活性層の屈折率に比べ約１０％小さくなる。電極１６
に正の電圧を電極１７に負の電圧を加えると活性層１４
は４２０ｎｍの波長で発光した。最大光出力は１３ｍＷ
であり、外部量子効率は３％であった。FIG. 2 shows a cross section of another example of a semiconductor light emitting device manufactured according to the present invention. This light-emitting device is composed of a nitride layer 11 (nitriding depth 50 °) formed on the surface of a sapphire (0001) substrate 10 and an AlN buffer layer 1 having a thickness of 500 °.
2. Si-doped n-type InAlN cladding layer 13 with a thickness of 5 μm, undoped InGaN active layer 1 with a thickness of 0.5 μm
4. A 2 μm-thick Mg-doped p-type InAlN cladding layer 15, a p-type cladding layer ohmic electrode 16, and an n-type cladding layer ohmic electrode 17. I shown here
The composition was selected so that the nAlN layer 13 and the InGaN layer 14 were lattice-matched to each other, and the band gap energy of the cladding layer was 0.3 eV or more larger than the band gap energy of the active layer. As a result, the refractive index of the cladding layer is about 10% smaller than that of the active layer. Electrode 16
When a positive voltage is applied to the electrode 17 and a negative voltage is applied to the electrode 17, the active layer 14
Emitted light at a wavelength of 420 nm. Maximum light output is 13mW
And the external quantum efficiency was 3%.
【００１５】この例では、ｎ型及びｐ型クラッド層とし
てＩｎＡｌＮを、また活性層としてＩｎＧａＮを用いた
が、互いに格子整合し、クラッド層のバンドギャップエ
ネルギが活性層のバンドギャップエネルギに比べ０．３
ｅＶ以上大きくなるという条件の下で組成を変化させる
ことにより、発光波長を１９０〜６５０ｎｍの範囲で変
化させることができる。In this example, InAlN was used as the n-type and p-type cladding layers, and InGaN was used as the active layer. However, they were lattice-matched to each other, and the bandgap energy of the cladding layer was 0.1% lower than that of the active layer. 3
The emission wavelength can be changed in the range of 190 to 650 nm by changing the composition under the condition that the voltage increases by eV or more.
【００１６】図３は、原料ガスとしてＩＩＩ族有機金属
とＮＨ３ を用いる場合について、本発明による半導体
発光素子の作製方法を実施するための成長装置の一例を
示すものである。図において、２０はサファイア（００
０１）基板、２１はカーボン・サセプタ、２２は石英反
応管、２３は高周波誘導コイル、２４は熱電対、２５は
有機金属ガス導入管、２６はＮＨ３ガス導入管、２７は
Ｈ２ガス及びＮ２ガス導入管、２８は排気口を示す。FIG. 3 shows an example of a growth apparatus for carrying out the method for manufacturing a semiconductor light emitting device according to the present invention when a group III organic metal and NH 3 are used as source gases. In the figure, 20 is sapphire (00
01) substrate, 21 is a carbon susceptor, 22 is a quartz reaction tube, 23 is a high frequency induction coil, 24 is a thermocouple, 25 is an organometallic gas introduction tube, 26 is an NH 3 gas introduction tube, 27 is H 2 gas and N 2 gas inlet, 28 denotes an exhaust port.
【００１７】この装置で、半導体発光素子用の多層膜構
造を作製するには、まず石英反応管２２内を真空排気装
置により排気する。次に、石英反応管２２内に０．５〜
２０ｌ／分のＨ２ガスを導入した後、高周波誘導コイル
２３を通電することによりカーボン・サセプタ２１を１
０００〜１３００℃に加熱し１〜６０分保持することに
より、サファイア（０００１）基板２０表面を清浄化す
る。続いて、Ｈ２ガスを０．５〜２０ｌ／分のＮＨ３ガ
スに切り替え１〜６０分保持することより、サファイア
（０００１）基板２０表面を単結晶ＡｌＮ化する。次
に、カーボン・サセプタ２１の温度を５００〜１０００
℃まで降温する。この状態で、バブラの温度を１５〜６
０℃に設定したトリメチルアルミニウム（ＴＭＡｌ）を
１〜１０００ｃｃ／分のＨ２ガス（あるいはＮ２もしく
はＡｒガス）でバブリングし、０〜２０ｌ／分のＨ２ガ
ス（あるいはＮ２もしくはＡｒガス）と合流させた後導
入管２５より石英反応管２２へ供給し単結晶もしくはア
モルファスのＡｌＮ層を堆積する。成長中の石英反応管
２２内の総ガス圧は４０〜１０００Ｔｏｒｒに調整す
る。ＡｌＮを１０〜２０００Å堆積させたところでＴＭ
Ａｌの石英反応管２２への供給を止め、カーボン・サセ
プタ２１を１０００〜１３００℃に加熱しＮＨ３雰囲気
中で１〜６０分保持することにより堆積したＡｌＮ膜を
単結晶化する。これに続けて、発光素子用のクラッド
層、活性層等の多層膜構造を作製する。In order to produce a multilayer structure for a semiconductor light emitting device using this apparatus, first, the inside of the quartz reaction tube 22 is evacuated by a vacuum evacuation apparatus. Next, 0.5 to 0.5
After introducing 20 l / min of H 2 gas, the high-frequency induction coil 23 is energized to set the carbon susceptor 21 to 1
The surface of the sapphire (0001) substrate 20 is cleaned by heating to 000 to 1300 ° C. and holding for 1 to 60 minutes. Subsequently, the surface of the sapphire (0001) substrate 20 is changed to single-crystal AlN by switching the H 2 gas to the NH 3 gas of 0.5 to 20 l / min and holding it for 1 to 60 minutes. Next, the temperature of the carbon susceptor 21 is set to 500 to 1000.
Cool down to ° C. In this state, the temperature of the bubbler
Trimethylaluminum set to 0 ℃ to (TMAl) was bubbled with 1～1000Cc / min H 2 gas (or N 2 or Ar gas), 0~20l / min H 2 gas (or N 2 or Ar gas) and After the merging, it is supplied from the introduction tube 25 to the quartz reaction tube 22 to deposit a single crystal or amorphous AlN layer. The total gas pressure in the growing quartz reaction tube 22 is adjusted to 40 to 1000 Torr. When AlN was deposited at 10 to 2000 °, TM
The supply of Al to the quartz reaction tube 22 is stopped, the carbon susceptor 21 is heated to 1000 to 1300 ° C., and kept in an NH 3 atmosphere for 1 to 60 minutes to monocrystallize the deposited AlN film. Subsequently, a multilayer film structure such as a cladding layer and an active layer for a light emitting element is manufactured.
【００１８】上記の実施例では、ＩＩＩ族原料及び窒素
原料としてＴＭＡｌ及びＮＨ３を用いたが、これに代え
てＴＥＡｌ等の他のＩＩＩ族有機金属あるいはＩＩＩ族
ハライド化物等の他のＩＩＩ族原料及びＮ２Ｈ２や有機
アミン等のその他の窒素原料を用いても同様の効果が得
られる。上記の実施例では、サファイア基板の面方位と
して（０００１）面を用いたが、これに代えて（０１１
２）面、（０１１０）面、（２１１０）面を用いても同
様の効果が得られる。In the above embodiment, TMAl and NH 3 were used as the group III raw material and the nitrogen raw material, but instead of this, another group III organic metal such as TEAl or another group III raw material such as a group III halide was used. The same effect can be obtained by using other nitrogen raw materials such as N 2 H 2 and organic amine. In the above embodiment, the (0001) plane was used as the plane orientation of the sapphire substrate.
Similar effects can be obtained by using the (2) plane, (0110) plane, and (2110) plane.
【００１９】[0019]
【発明の効果】本発明では予め窒化処理することによっ
てＡｌＮ化したサファイア表面に多結晶もしくはアモル
ファスＡｌＮバッファ層を低温堆積するため、図４の示
すとおり成長初期の時間遅れを生ずることなく成長を開
始できる。このため、ＡｌＮバッファ層の膜厚制御を精
密に再現性よく行うことができる。これはＡｌＮの堆積
に先立ってサファイア表面をＡｌＮ化させておいたた
め、アルミニウム原料ガスの基板表面への到達と同時に
堆積が開始するためである。また、表面窒化層上にＡｌ
Ｎを堆積する場合には、未処理のサファイア基板に直接
堆積する場合に比べより薄い膜厚で連続膜となる上、平
坦性にも優れるという利点をもつ。さらに、サファイア
基板上に形成した窒化層はその上に堆積したＡｌＮバッ
ファ層の結晶性を向上させる効果を有するため、その上
に成長したエピタキシャル膜の特性をも向上させる。ま
た、低温堆積したＡｌＮ層は窒化処理によりサファイア
表面に生じた原子オーダーの凹凸を平坦化する作用を有
するため、サファイア表面窒化層上に直接ＩＩＩ族窒化
物半導体薄膜をエピタキシャル成長する際に問題となる
三次元成長を抑制することができる。According to the present invention, since a polycrystalline or amorphous AlN buffer layer is deposited at a low temperature on the sapphire surface which has been converted to AlN by pre-nitriding, the growth is started without a time delay in the initial growth as shown in FIG. it can. Therefore, the thickness of the AlN buffer layer can be controlled precisely and with good reproducibility. This is because the sapphire surface was converted to AlN prior to the deposition of AlN, so that the deposition started simultaneously with the aluminum source gas reaching the substrate surface. Also, Al on the surface nitrided layer
In the case of depositing N, there is an advantage that a thin film is formed as a continuous film and the flatness is excellent as compared with the case where N is directly deposited on an untreated sapphire substrate. Further, since the nitride layer formed on the sapphire substrate has the effect of improving the crystallinity of the AlN buffer layer deposited thereon, the characteristics of the epitaxial film grown thereon are also improved. Further, since the AlN layer deposited at a low temperature has a function of flattening irregularities on the order of atoms generated on the sapphire surface by the nitriding treatment, it becomes a problem when the group III nitride semiconductor thin film is epitaxially grown directly on the sapphire surface nitride layer. Three-dimensional growth can be suppressed.
【００２０】この結果、本発明によれば高効率・長寿命
の半導体発光素子を再現性よく作製することができる。
特に、サファイア基板上に形成した窒化層がその上に堆
積するＡｌＮ層の初期段階における膜厚制御性及びその
平坦性や結晶性を向上させることは、全く新規の効果で
ある。As a result, according to the present invention, a semiconductor light emitting device having high efficiency and long life can be manufactured with good reproducibility.
In particular, the improvement of the controllability of the thickness of the AlN layer deposited on the sapphire substrate on the AlN layer deposited on the sapphire substrate and the improvement of its flatness and crystallinity are completely novel effects.
【図１】本発明によって作製された半導体発光素子の一
例。FIG. 1 is an example of a semiconductor light emitting device manufactured according to the present invention.
【図２】本発明によって作製された半導体発光素子の他
の例。FIG. 2 is another example of a semiconductor light emitting device manufactured according to the present invention.
【図３】本発明の半導体発光素子を作製する際に用いた
化合物半導体薄膜のエピタキシャル成長装置。FIG. 3 shows an apparatus for epitaxially growing a compound semiconductor thin film used in producing the semiconductor light emitting device of the present invention.
【図４】窒化処理したサファイア基板上でのＡｌＮ成長
初期段階における成長膜厚の成長時間依存性を示す。FIG. 4 shows the growth time dependence of the growth film thickness in the initial stage of AlN growth on a sapphire substrate subjected to nitriding treatment.
【図５】未処理サファイア基板上でのＡｌＮ成長初期段
階における成長膜厚の成長時間依存性を示す。FIG. 5 shows the growth time dependence of the growth film thickness in the initial stage of AlN growth on an untreated sapphire substrate.
１ サファイア（０００１）基板 ２ サファイア表面窒化層 ３ ＡｌＮバッファ層 ４ Ｓｉドープｎ型低抵抗ＧａＮ層 ５ Ｚｎドープ半絶縁ＧａＮ発光層 ６ 半絶縁層の電極 ７ ｎ型低抵抗層のオーミック電極 １０ サファイア（０００１）基板 １１ サファイア表面窒化層 １２ ＡｌＮバッファ層 １３ Ｓｉドープｎ型ＩｎＡｌＮクラッド層 １４ アンドープＩｎＧａＮ活性層 １５ Ｍｇドープｐ型ＩｎＡｌＮクラッド層 １６ ｐ型クラッド層のオーミック電極 １７ ｎ型クラッド層のオーミック電極 ２０ サファイア（０００１）基板 ２１ カーボン・サセプタ ２２ 石英反応管 ２３ 高周波誘導コイル ２４ 熱電対 ２５ 有機金属ガス導入管 ２６ ＮＨ３ガス導入管 ２７ Ｈ２ガス及びＮ２ガス導入管 ２８ 排気口Reference Signs List 1 sapphire (0001) substrate 2 sapphire surface nitride layer 3 AlN buffer layer 4 Si-doped n-type low-resistance GaN layer 5 Zn-doped semi-insulating GaN light-emitting layer 6 electrode of semi-insulating layer 7 ohmic electrode of n-type low-resistance layer 10 sapphire ( 0001) Substrate 11 Sapphire surface nitride layer 12 AlN buffer layer 13 Si-doped n-type InAlN cladding layer 14 undoped InGaN active layer 15 Mg-doped p-type InAlN cladding layer 16 ohmic electrode of p-type cladding layer 17 ohmic electrode of n-type cladding layer 20 Sapphire (0001) substrate 21 Carbon susceptor 22 Quartz reaction tube 23 High frequency induction coil 24 Thermocouple 25 Organometallic gas introduction tube 26 NH 3 gas introduction tube 27 H 2 gas and N 2 gas introduction tube 28 Exhaust port
フロントページの続き (56)参考文献 特開 平３−203388（ＪＰ，Ａ) 特開 平２−229476（ＪＰ，Ａ) 特開 昭63−178516（ＪＰ，Ａ) 1990年（平成２年）秋季第51回応用物 理学会学術講演会予稿集第１分冊 28ａ −ＳＸ−18 ｐ．305 日本結晶成長学会誌 Ｖｏｌ．13 Ｎ ｏ．４（1986）ｐ．218−225 電子情報通信学会技術研究報告 Ｖｏ ｌ．88 Ｎｏ．199 ＥＤ88−79（1988) ｐ．７−12 (58)調査した分野(Int.Cl.7，ＤＢ名) H01L 33/00 H01L 21/205 Continuation of the front page (56) References JP-A-3-203388 (JP, A) JP-A-2-229476 (JP, A) JP-A-63-178516 (JP, A) Fall of 1990 (Heisei 2) Proceedings of the 51st Annual Meeting of the Japan Society of Applied Science, Volume 1 28a-SX-18 p. 305 Journal of the Japanese Association for Crystal Growth Vol. 13 No. 4 (1986) p. 218-225 IEICE Technical Report Vol. 88 No. 199 ED88-79 (1988) p. 7-12 (58) Field surveyed (Int. Cl. 7 , DB name) H01L 33/00 H01L 21/205
Claims (2)
で熱処理し、基板表面を単結晶ＡｌＮ化する第１の工程
と、窒化層上にアルミニウム原料ガスとの反応により多
結晶もしくはアモルファスＡｌＮバッファ層を堆積する
第２の工程と、前記ＡｌＮバッファ層をその堆積温度よ
りも高温でアニールする第３の工程と、ＩｎＧａＡｌＮ
層を少なくとも１層含む発光層を形成する第４の工程と
を含むことを特徴とする半導体発光素子の作製方法。A sapphire substrate is heat-treated in a nitrogen source gas atmosphere to convert the substrate surface into single crystal AlN, and a polycrystalline or amorphous AlN buffer layer is formed on the nitride layer by a reaction with an aluminum source gas. A second step of depositing; a third step of annealing the AlN buffer layer at a temperature higher than its deposition temperature;
And a fourth step of forming a light emitting layer including at least one layer.
ニウム，ハロゲン化アルミニウムあるいは金属アルミニ
ウム蒸気のいずれか１つ、窒素原料ガスとしてはＮ
Ｈ３，Ｎ２Ｈ２あるいは有機アミンのいずれか１つから
選ばれることを特徴とする請求項１記載の半導体発光素
子の作製方法。2. An aluminum source gas of one of organic aluminum, aluminum halide or metal aluminum vapor, and a nitrogen source gas of N
H 3, N 2 H 2 or a method for manufacturing a semiconductor light emitting device according to claim 1, wherein the selected from one of an organic amine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21917991A JP3147316B2 (en) | 1991-08-05 | 1991-08-05 | Method for manufacturing semiconductor light emitting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21917991A JP3147316B2 (en) | 1991-08-05 | 1991-08-05 | Method for manufacturing semiconductor light emitting device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0541541A JPH0541541A (en) | 1993-02-19 |
| JP3147316B2 true JP3147316B2 (en) | 2001-03-19 |
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ID=16731440
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| Application Number | Title | Priority Date | Filing Date |
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| JP21917991A Expired - Fee Related JP3147316B2 (en) | 1991-08-05 | 1991-08-05 | Method for manufacturing semiconductor light emitting device |
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Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5656832A (en) | 1994-03-09 | 1997-08-12 | Kabushiki Kaisha Toshiba | Semiconductor heterojunction device with ALN buffer layer of 3nm-10nm average film thickness |
| US6136626A (en) * | 1994-06-09 | 2000-10-24 | Matsushita Electric Industrial Co., Ltd. | Semiconductor light-emitting device and production method thereof |
| US5751013A (en) * | 1994-07-21 | 1998-05-12 | Matsushita Electric Industrial Co., Ltd. | Semiconductor light-emitting device and production method thereof |
| WO1997011518A1 (en) | 1995-09-18 | 1997-03-27 | Hitachi, Ltd. | Semiconductor material, method of producing the semiconductor material, and semiconductor device |
| JP3423897B2 (en) | 1999-04-01 | 2003-07-07 | 宮崎沖電気株式会社 | Method for manufacturing semiconductor device |
| KR20010029852A (en) | 1999-06-30 | 2001-04-16 | 도다 다다히데 | Group ⅲ nitride compound semiconductor device and producing method therefor |
| JP3589114B2 (en) * | 1999-09-21 | 2004-11-17 | 日立電線株式会社 | Insecticide |
| JP4963763B2 (en) * | 2000-12-21 | 2012-06-27 | 日本碍子株式会社 | Semiconductor element |
| JP4260380B2 (en) * | 2001-06-12 | 2009-04-30 | 日本碍子株式会社 | Method for producing group III nitride film, sapphire single crystal substrate for producing group III nitride film, and substrate for epitaxial growth |
| JP2007073975A (en) * | 2004-06-29 | 2007-03-22 | Ngk Insulators Ltd | Quality improvement method of group iii nitride crystal, substrate for epitaxial growth, and semiconductor element |
| JP4712450B2 (en) | 2004-06-29 | 2011-06-29 | 日本碍子株式会社 | Method for improving surface flatness of AlN crystal |
| JP5159040B2 (en) * | 2005-03-31 | 2013-03-06 | 株式会社光波 | Method for forming low temperature growth buffer layer and method for manufacturing light emitting device |
| JP5236148B2 (en) * | 2005-05-12 | 2013-07-17 | 日本碍子株式会社 | EPITAXIAL SUBSTRATE, SEMICONDUCTOR DEVICE, METHOD FOR MANUFACTURING EPITAXIAL SUBSTRATE, METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE, AND METHOD FOR ALIGNING DISLOCATION IN GROUP III NITRIDE CRYSTAL |
| KR100667506B1 (en) * | 2005-08-02 | 2007-01-10 | 엘지전자 주식회사 | Led with metal nitride layer and method of forming the same |
| KR100766858B1 (en) * | 2006-03-16 | 2007-10-12 | 서울옵토디바이스주식회사 | Method for forming buffer layer for a light emitting device of a nitride compound semiconductor and light emitting device of a nitride compound semiconductor thereof |
| JP5071703B2 (en) * | 2006-08-08 | 2012-11-14 | 独立行政法人物質・材料研究機構 | Semiconductor manufacturing equipment |
| JP4823856B2 (en) * | 2006-11-01 | 2011-11-24 | 国立大学法人三重大学 | Method for producing AlN group III nitride single crystal thick film |
| JP6131908B2 (en) * | 2014-05-08 | 2017-05-24 | 豊田合成株式会社 | Group III nitride semiconductor manufacturing method and light emitting device manufacturing method |
| CN107078030B (en) * | 2015-09-11 | 2022-08-23 | 国立大学法人三重大学 | Method for manufacturing nitride semiconductor substrate |
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1991
- 1991-08-05 JP JP21917991A patent/JP3147316B2/en not_active Expired - Fee Related
Non-Patent Citations (3)
| Title |
|---|
| １９９０年（平成２年）秋季第５１回応用物理学会学術講演会予稿集第１分冊 ２８ａ−ＳＸ−１８ ｐ．３０５ |
| 日本結晶成長学会誌 Ｖｏｌ．１３ Ｎｏ．４（１９８６）ｐ．２１８−２２５ |
| 電子情報通信学会技術研究報告 Ｖｏｌ．８８ Ｎｏ．１９９ ＥＤ８８−７９（１９８８）ｐ．７−１２ |
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